Fermentation of sugars in organe peel hydrolysates to ethanol by recombinantEscherichia coli KO11

Abstract
The conversion of monosaccharides in organe peel hydrolysates to ethanol by recombinantEscherichia coli KO11 has been investigated in pH-controlled batch fermentations at 32 and 37°C. pH values and concentration of peel hydrolysate were varied to determine approximate optimal conditions and limitations of these fermentations. Very high yields of ethanol were achieved by this microorganism at reasonable ethanol concentrations (28–48 g/L). The pH range between 5.8 and 6.2 appears to be optimal. The microorganism can convert all major monosaccharides in organe peel hydrolysates to ethanol and to smaller amounts of acetic and lactic acids. Acetic acid is coproduced in equimolar amounts with ethanol by catabolism of salts of galacturonic acid.